1
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Azizi K, Laio A, Hassanali A. Solvation thermodynamics from cavity shapes of amino acids. PNAS NEXUS 2023; 2:pgad239. [PMID: 37545648 PMCID: PMC10400782 DOI: 10.1093/pnasnexus/pgad239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 07/07/2023] [Accepted: 07/17/2023] [Indexed: 08/08/2023]
Abstract
According to common physical chemistry wisdom, the solvent cavities hosting a solute are tightly sewn around it, practically coinciding with its van der Waals surface. Solvation entropy is primarily determined by the surface and the volume of the cavity while enthalpy is determined by the solute-solvent interaction. In this work, we challenge this picture, demonstrating by molecular dynamics simulations that the cavities surrounding the 20 amino acids deviate significantly from the molecular surface. Strikingly, the shape of the cavity alone can be used to predict the solvation free energy, entropy, enthalpy, and hydrophobicity. Solute-solvent interactions involving the different chemical moieties of the amino acid, determine indirectly the cavity shape, and the properties of the branches but do not have to be taken explicitly into account in the prediction model.
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Affiliation(s)
- Khatereh Azizi
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Alessandro Laio
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
- SISSA, Via Bonomea 265, I-34136 Trieste, Italy
| | - Ali Hassanali
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
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2
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Schönfeldová T, Dupertuis N, Chen Y, Ansari N, Poli E, Wilkins DM, Hassanali A, Roke S. Charge Gradients around Dendritic Voids Cause Nanoscale Inhomogeneities in Liquid Water. J Phys Chem Lett 2022; 13:7462-7468. [PMID: 35930807 DOI: 10.1021/acs.jpclett.2c01872] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Water is the matrix of life and serves as a solvent for numerous physical and chemical processes. The origins of the nature of inhomogeneities that exist in liquid water and the time scales over which they occur remains an open question. Here, we report femtosecond elastic second harmonic scattering (fs-ESHS) of liquid water in comparison to an isotropic liquid (CCl4) and show that water is indeed a nonuniform liquid. The coherent fs-ESHS intensity was interpreted, using molecular dynamics simulations, as arising from charge density fluctuations with enhanced nanoscale polarizabilities around transient voids having an average lifetime of 300 fs. Although voids were also present in CCl4, they were not characterized by hydrogen bond defects and did not show strong polarizability fluctuations, leading to fs-ESHS of an isotropic liquid. The voids increased in number at higher temperatures above room temperature, in agreement with the fs-ESHS results.
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Affiliation(s)
- Tereza Schönfeldová
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bio-engineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Nathan Dupertuis
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bio-engineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Yixing Chen
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bio-engineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Narjes Ansari
- Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy
| | - Emiliano Poli
- Condensed Matter and Statistical Physics (CMSP), The Abdus Salam International Center For Theoretical Physics, 34151 Trieste, Italy
| | - David M Wilkins
- Atomistic Simulation Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, Northern Ireland, United Kingdom
| | - Ali Hassanali
- Condensed Matter and Statistical Physics (CMSP), The Abdus Salam International Center For Theoretical Physics, 34151 Trieste, Italy
| | - Sylvie Roke
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bio-engineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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3
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Capelli R, Muniz-Miranda F, Pavan GM. Ephemeral ice-like local environments in classical rigid models of liquid water. J Chem Phys 2022; 156:214503. [DOI: 10.1063/5.0088599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Despite great efforts over the past 50 years, the simulation of water still presents significant challenges and open questions. At room temperature and pressure, the collective molecular interactions and dynamics of water molecules may form local structural arrangements that are non-trivial to classify. Here, we employ a data-driven approach built on Smooth Overlap of Atomic Position (SOAP) that allows us to compare and classify how widely used classical models represent liquid water. Macroscopically, the obtained results are rationalized based on water thermodynamic observables. Microscopically, we directly observe how transient ice-like ordered environments may dynamically/statistically form in liquid water, even above freezing temperature, by comparing the SOAP spectra for different ice structures with those of the simulated liquid systems. This confirms recent ab initio-based calculations but also reveals how the emergence of ephemeral local ice-like environments in liquid water at room conditions can be captured by classical water models.
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Affiliation(s)
- Riccardo Capelli
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy
| | - Francesco Muniz-Miranda
- Department of Chemical and Geological Sciences, University of Modena and Reggio-Emilia, Via Campi 103, I-41125 Modena, Italy
| | - Giovanni M. Pavan
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy
- Department of Innovative Technologies, University of Applied Sciences and Arts of Southern Switzerland, Polo Universitario Lugano, Campus Est, Via la Santa 1, CH-6962 Lugano-Viganello, Switzerland
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4
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Villa AM, Doglia SM, De Gioia L, Natalello A, Bertini L. Fluorescence of KCl Aqueous Solution: A Possible Spectroscopic Signature of Nucleation. J Phys Chem B 2022; 126:2564-2572. [PMID: 35344657 PMCID: PMC8996234 DOI: 10.1021/acs.jpcb.2c01496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
![]()
Ion pairing
in water solutions alters both the water hydrogen-bond network and
ion solvation, modifying the dynamics and properties of electrolyte
water solutions. Here, we report an anomalous intrinsic fluorescence
of KCl aqueous solution at room temperature and show that its intensity
increases with the salt concentration. From the ab initio density
functional theory (DFT) and time-dependent DFT modeling, we propose
that the fluorescence emission could originate from the stiffening
of the hydrogen bond network in the hydration shell of solvated ion-pairs
that suppresses the fast nonradiative decay and allows the slower
radiative channel to become a possible decay pathway. Because computations
suggest that the fluorophores are the local ion-water structures present
in the prenucleation phase, this band could be the signature of the
incoming salt precipitation.
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Affiliation(s)
- Anna Maria Villa
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Silvia Maria Doglia
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Luca De Gioia
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Antonino Natalello
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Luca Bertini
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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5
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Azizi K, Laio A, Hassanali A. Model Folded Hydrophobic Polymers Reside in Highly Branched Voids. J Phys Chem Lett 2022; 13:183-189. [PMID: 34965118 DOI: 10.1021/acs.jpclett.1c03333] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
By using advanced data analysis techniques, we characterize the shape of the voids surrounding model polymers of different sizes in water, observed in molecular dynamics simulations. We find that even when the model polymer is folded, the voids are extremely rough, with branches that can extend to over 1 nm away from the polymer. Water molecules in contact with the void retain close-to-bulk properties in terms of local structure. The branches disappear, and the voids start resembling the quasispherical shape predicted by dewetting theory only when they surround particles with a radius ∼1 nm, well above the size occupied by a folded hydrophobic polymer. Our results provide fresh insights into the microscopic origins of the vapor-like interfaces underlying dewetting and drying transitions.
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Affiliation(s)
- Khatereh Azizi
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Alessandro Laio
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
- SISSA, Via Bonomea 265, I-34136 Trieste, Italy
| | - Ali Hassanali
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
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6
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Butts CT, Martin RW. Bayesian estimation of the hydroxyl radical diffusion coefficient at low temperature and high pressure from atomistic molecular dynamics. J Chem Phys 2021; 155:194504. [PMID: 34800943 DOI: 10.1063/5.0064995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The hydroxyl radical is the primary reactive oxygen species produced by the radiolysis of water and is a significant source of radiation damage to living organisms. Mobility of the hydroxyl radical at low temperatures and/or high pressures is hence a potentially important factor in determining the challenges facing psychrophilic and/or barophilic organisms in high-radiation environments (e.g., ice-interface or undersea environments in which radiative heating is a potential heat and energy source). Here, we estimate the diffusion coefficient for the hydroxyl radical in aqueous solution using a hierarchical Bayesian model based on atomistic molecular dynamics trajectories in TIP4P/2005 water over a range of temperatures and pressures.
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Affiliation(s)
- Carter T Butts
- Departments of Sociology, Statistics, Computer Science, and EECS, University of California, Irvine, California 92697, USA
| | - Rachel W Martin
- Departments of Chemistry and Molecular Biology and Biochemistry, University of California, Irvine, California 92697, USA
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7
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Size dependence of hydrophobic hydration at electrified gold/water interfaces. Proc Natl Acad Sci U S A 2021; 118:2023867118. [PMID: 33876767 DOI: 10.1073/pnas.2023867118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hydrophobic hydration at metal/water interfaces actively contributes to the energetics of electrochemical reactions, e.g. [Formula: see text] and [Formula: see text] reduction, where small hydrophobic molecules are involved. In this work, constant applied potential molecular dynamics is employed to study hydrophobic hydration at a gold/water interface. We propose an adaptation of the Lum-Chandler-Weeks (LCW) theory to describe the free energy of hydrophobic hydration at the interface as a function of solute size and applied voltage. Based on this model we are able to predict the free energy cost of cavity formation at the interface directly from the free energy cost in the bulk plus an interface-dependent correction term. The interfacial water network contributes significantly to the free energy, yielding a preference for outer-sphere adsorption at the gold surface for ideal hydrophobes. We predict an accumulation of small hydrophobic solutes of sizes comparable to CO or [Formula: see text], while the free energy cost to hydrate larger hydrophobes, above 2.5-Å radius, is shown to be greater at the interface than in the bulk. Interestingly, the transition from the volume dominated to the surface dominated regimes predicted by the LCW theory in the bulk is also found to take place for hydrophobes at the Au/water interface but occurs at smaller cavity radii. By applying the adapted LCW theory to a simple model addition reaction, we illustrate some implications of our findings for electrochemical reactions.
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8
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On the existence of soliton-like collective modes in liquid water at the viscoelastic crossover. Sci Rep 2021; 11:5417. [PMID: 33686146 PMCID: PMC7940660 DOI: 10.1038/s41598-021-84277-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 02/04/2021] [Indexed: 11/11/2022] Open
Abstract
The problem of large-density variations in supercooled and ambient water has been widely discussed in the past years. Recent studies have indicated the possibility of nanometer-sized density variations on the subpicosecond and picosecond time scales. The nature of fluctuating density heterogeneities remains a highly debated issue. In the present work, we address the problem of possible association of such density variations with the dynamics of terahertz longitudinal acoustic-like modes in liquid water. Our study is based on the fact that the subpicosecond dynamics of liquid water are essentially governed by the structural relaxation. Using a mode coupling theory approach, we found that for typical values of parameters of liquid water, the dynamic mechanism coming from the combination of the structural relaxation process and the finiteness of the amplitude of terahertz longitudinal acoustic-like mode gives rise to a soliton-like collective mode on a temperature-dependent nanometer length scale. The characteristics of this mode are consistent with the estimates of the amplitudes and temperature-dependent correlation lengths of density fluctuations in liquid water obtained in experiments and simulations. Thus, the fully dynamic mechanism could contribute to the formation and dynamics of fluctuating density heterogeneities. The soliton-like collective excitations suggested by our analysis may be relevant to different phenomena connected with supercooled water and can be expected to be associated with some ultrafast biological processes.
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9
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10
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Cuny J, Cerda Calatayud J, Ansari N, Hassanali AA, Rapacioli M, Simon A. Simulation of Liquids with the Tight-Binding Density-Functional Approach and Improved Atomic Charges. J Phys Chem B 2020; 124:7421-7432. [PMID: 32696649 DOI: 10.1021/acs.jpcb.0c04167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Theoretical description of liquids, especially liquid water, is an ongoing subject with important implications in various domains such as homogeneous catalysis; solvation of molecular, ionic, and biomolecular species; and reactivity. Various formalisms exist to describe liquids, each one displaying its own balance between accuracy and computational cost that defines its range of applications. The present article revisits the ability of the density-functional-based tight-binding (SCC-DFTB) approach to model liquids by focusing on liquid water and liquid benzene under ambient conditions. To do so, we benchmark a recent correction for the SCC-DFTB atomic charges that allows for a drastic improvement of the pair radial distribution functions of liquid water as compared to both experimental data and density-functional theory results performed in the generalized-gradient approximation. We also report the coupling of the deMonNano and i-PI codes to perform path-integral molecular dynamics. This allows us to rationalize the impact of nuclear quantum effects on the SCC-DFTB description of liquid water. This study evidences the rather good ability of SCC-DFTB to describe liquid water and liquid benzene. As the first example of application, we also present results for a benzene molecule solvated in water with the perspectives of further studies devoted to solvent/water interfaces.
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Affiliation(s)
- Jérôme Cuny
- Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Jesus Cerda Calatayud
- Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Narjes Ansari
- The Abdus Salam International Center for Theoretical Physics, Condensed Matter and Statistical Physics Section, Strada Costiera 11, 34151 Trieste, Italy.,Department of Chemistry and Applied Biosciences, ETH Zurich, 3 c/o USI Campus, Via Giuseppe Buffi13, 6900 Lugano, Switzerland.,Facoltà di informatica, Istituto di Scienze Computazionali, Università della Svizzera Italiana, CH-6900 Lugano, Switzerland
| | - Ali A Hassanali
- The Abdus Salam International Center for Theoretical Physics, Condensed Matter and Statistical Physics Section, Strada Costiera 11, 34151 Trieste, Italy
| | - Mathias Rapacioli
- Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Aude Simon
- Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
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11
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Ansari N, Karmakar T, Parrinello M. Molecular Mechanism of Gas Solubility in Liquid: Constant Chemical Potential Molecular Dynamics Simulations. J Chem Theory Comput 2020; 16:5279-5286. [PMID: 32551636 DOI: 10.1021/acs.jctc.0c00450] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Accurate prediction of gas solubility in a liquid is crucial in many areas of chemistry, and a detailed understanding of the molecular mechanism of the gas solvation continues to be an active area of research. Here, we extend the idea of the constant chemical potential molecular dynamics (CμMD) approach to the calculation of the gas solubility in the liquid under constant gas chemical potential conditions. As a representative example, we utilize this method to calculate the isothermal solubility of carbon dioxide in water. Additionally, we provide microscopic insight into the mechanism of solvation that preferentially occurs in areas of the surface where the hydrogen network is broken.
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Affiliation(s)
- Narjes Ansari
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8092 Zurich, Switzerland.,Facoltà di informatica, Istituto di Scienze Computazionali, Università della Svizzera Italiana, CH-6900 Lugano, Switzerland
| | - Tarak Karmakar
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8092 Zurich, Switzerland.,Facoltà di informatica, Istituto di Scienze Computazionali, Università della Svizzera Italiana, CH-6900 Lugano, Switzerland
| | - Michele Parrinello
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8092 Zurich, Switzerland.,Facoltà di informatica, Istituto di Scienze Computazionali, Università della Svizzera Italiana, CH-6900 Lugano, Switzerland.,Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy
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12
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Ansari N, Onat B, Sosso GC, Hassanali A. Insights into the Emerging Networks of Voids in Simulated Supercooled Water. J Phys Chem B 2020; 124:2180-2190. [PMID: 32032486 DOI: 10.1021/acs.jpcb.9b10144] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The structural evolution of supercooled liquid water as we approach the glass transition temperature continues to be an active area of research. Here, we use molecular dynamics simulations of TIP4P/ice water to study the changes in the connected regions of empty space within the liquid, which we investigate using the Voronoi-voids network. We observe two important features: supercooling enhances the fraction of nonspherical voids and different sizes of voids tend to cluster forming a percolating network. By examining order parameters such as the local structure index (LSI), tetrahedrality and topological defects, we show that water molecules near large void clusters tend to be slightly more tetrahedral than those near small voids, with a lower population of under- and overcoordinated defects. We show further that the distribution of closed rings of water molecules around small and large void clusters maintain a balance between 6 and 7 membered rings. Our results highlight the changes of the dual voids and water network as a structural hallmark of supercooling and provide insights into the molecular origins of cooperative effects underlying density fluctuations on the subnanometer and nanometer length scale. In addition, the percolation of the voids and the hydrogen bond network around the voids may serve as useful order parameters to investigate density fluctuations in supercooled water.
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Affiliation(s)
- Narjes Ansari
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Berk Onat
- Department of Chemistry and Centre for Scientific Computing, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom.,School of Engineering, University of Warwick, Gibbet Hill, Coventry CV4 7AL, United Kingdom
| | - Gabriele C Sosso
- Department of Chemistry and Centre for Scientific Computing, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
| | - Ali Hassanali
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
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13
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Villa AM, Doglia SM, De Gioia L, Bertini L, Natalello A. Anomalous Intrinsic Fluorescence of HCl and NaOH Aqueous Solutions. J Phys Chem Lett 2019; 10:7230-7236. [PMID: 31689111 DOI: 10.1021/acs.jpclett.9b02163] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The unique properties of liquid water mainly arise from its hydrogen bond network. The geometry and dynamics of this network play a key role in shaping the characteristics of soft matter, from simple solutions to biosystems. Here we report an anomalous intrinsic fluorescence of HCl and NaOH aqueous solutions at room temperature that shows important differences in the excitation and emission bands between the two solutes. From ab initio time-dependent density functional theory modeling we propose that fluorescence emission could originate from hydrated ion species contained in transient cavities of the bulk solvent. These cavities, which are characterized by a stiff surface, could provide an environment that, upon trapping the excited state, suppresses the fast nonradiative decay and allows the slower radiative channel to become a possible decay pathway.
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Affiliation(s)
- Anna Maria Villa
- Department of Biotechnology and Biosciences , University of Milano-Bicocca , Piazza della Scienza 2 , 20126 Milan , Italy
| | - Silvia Maria Doglia
- Department of Biotechnology and Biosciences , University of Milano-Bicocca , Piazza della Scienza 2 , 20126 Milan , Italy
| | - Luca De Gioia
- Department of Biotechnology and Biosciences , University of Milano-Bicocca , Piazza della Scienza 2 , 20126 Milan , Italy
| | - Luca Bertini
- Department of Biotechnology and Biosciences , University of Milano-Bicocca , Piazza della Scienza 2 , 20126 Milan , Italy
| | - Antonino Natalello
- Department of Biotechnology and Biosciences , University of Milano-Bicocca , Piazza della Scienza 2 , 20126 Milan , Italy
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14
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Ansari N, Laio A, Hassanali A. Spontaneously Forming Dendritic Voids in Liquid Water Can Host Small Polymers. J Phys Chem Lett 2019; 10:5585-5591. [PMID: 31469575 DOI: 10.1021/acs.jpclett.9b02052] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Some liquids are characterized by the presence of large voids with dendritic shapes and for this reason are dubbed transiently porous. By using a battery of data analysis tools, we demonstrate that liquid water and methane are both characterized by transient porosity. We show that the thermodynamics of porosity is distinct from that associated with cavitation á la classical nucleation theory. The shapes of dendritic voids in both liquids with very different chemistries resemble those of small polymers. We further show, using free energy calculations, that the cost of solvating small hydrophobic polymers in water is consistent with the work associated with creating dendritic voids. The entropic and enthalpic contributions associated with hosting these polymers can thus be rationalized by the thermodynamics of fluctuations in bulk water.
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Affiliation(s)
- Narjes Ansari
- The Abdus Salam International Centre for Theoretical Physics , Strada Costiera 11 , 34151 Trieste , Italy
| | - Alessandro Laio
- The Abdus Salam International Centre for Theoretical Physics , Strada Costiera 11 , 34151 Trieste , Italy
- SISSA , Via Bonomea 265 , I-34136 Trieste , Italy
| | - Ali Hassanali
- The Abdus Salam International Centre for Theoretical Physics , Strada Costiera 11 , 34151 Trieste , Italy
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15
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Rego NB, Xi E, Patel AJ. Protein Hydration Waters Are Susceptible to Unfavorable Perturbations. J Am Chem Soc 2019; 141:2080-2086. [DOI: 10.1021/jacs.8b11448] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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16
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Ansari N, Dandekar R, Caravati S, Sosso GC, Hassanali A. High and low density patches in simulated liquid water. J Chem Phys 2018; 149:204507. [PMID: 30501251 DOI: 10.1063/1.5053559] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We present insights into the nature of structural heterogeneities in liquid water by characterizing the empty space within the hydrogen bond network. Using molecular dynamics simulations, we show that density fluctuations create regions of empty space characterized by a diverse morphology - from spherical to fractal-like voids. These voids allow for the identification of low and high density patches of the liquid, encompassing short (0.3-0.5 nm) as well as long (1-2 nm) length-scales. In addition, we show that the formation of these patches is coupled to collective fluctuations involving the topology of hydrogen-bonded rings of water molecules. In particular, water molecules in the high density patches tend to be slightly more tetrahedral - which is consistent with the predictions of the hydrophobic effect.
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Affiliation(s)
- N Ansari
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - R Dandekar
- The Institute of Mathematical Sciences-HBNI, 4th Cross Street, CIT Campus, Tharamani, Chennai, India
| | - S Caravati
- Department of Chemistry, University of Zurich, Winterhurerstrasse 190, Zurich CH-8057, Switzerland
| | - G C Sosso
- Department of Chemistry and Centre for Scientific Computing, University of Warwick, Gibbet Hill, Coventry CV4 7AL, United Kingdom
| | - A Hassanali
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
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17
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Ulman K, Busch S, Hassanali AA. Quantum mechanical effects in zwitterionic amino acids: The case of proline, hydroxyproline, and alanine in water. J Chem Phys 2018; 148:222826. [DOI: 10.1063/1.5008665] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kanchan Ulman
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Sebastian Busch
- German Engineering Materials Science Centre (GEMS) at Heinz Maier-Leibnitz Zentrum (MLZ), Helmholtz-Zentrum Geesthacht GmbH, Lichtenbergstr. 1, 85747 Garching bei München, Germany
| | - Ali A. Hassanali
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
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18
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Dandekar R, Hassanali AA. Hierarchical lattice models of hydrogen-bond networks in water. Phys Rev E 2018; 97:062113. [PMID: 30011567 DOI: 10.1103/physreve.97.062113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Indexed: 06/08/2023]
Abstract
We develop a graph-based model of the hydrogen-bond network in water, with a view toward quantitatively modeling the molecular-level correlational structure of the network. The networks formed are studied by the constructing the model on two infinite-dimensional lattices. Our models are built bottom up, based on microscopic information coming from atomistic simulations, and we show that the predictions of the model are consistent with known results from ab initio simulations of liquid water. We show that simple entropic models can predict the correlations and clustering of local-coordination defects around tetrahedral waters observed in the atomistic simulations. We also find that orientational correlations between bonds are longer ranged than density correlations, determine the directional correlations within closed loops, and show that the patterns of water wires within these structures are also consistent with previous atomistic simulations. Our models show the existence of density and compressibility anomalies, as seen in the real liquid, and the phase diagram of these models is consistent with the singularity-free scenario previously proposed by Sastry and coworkers [Phys. Rev. E 53, 6144 (1996)1063-651X10.1103/PhysRevE.53.6144].
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Affiliation(s)
- Rahul Dandekar
- Condensed Matter and Statistical Physics Section, International Center for Theoretical Physics, Strada Costiera 11, Trieste, Italy
| | - Ali A Hassanali
- Condensed Matter and Statistical Physics Section, International Center for Theoretical Physics, Strada Costiera 11, Trieste, Italy
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Xi E, Marks SM, Fialoke S, Patel AJ. Sparse sampling of water density fluctuations near liquid-vapor coexistence. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1457218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Erte Xi
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, PA, USA
| | - Sean M. Marks
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, PA, USA
| | - Suruchi Fialoke
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, PA, USA
| | - Amish J. Patel
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, PA, USA
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Brini E, Fennell CJ, Fernandez-Serra M, Hribar-Lee B, Lukšič M, Dill KA. How Water's Properties Are Encoded in Its Molecular Structure and Energies. Chem Rev 2017; 117:12385-12414. [PMID: 28949513 PMCID: PMC5639468 DOI: 10.1021/acs.chemrev.7b00259] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Indexed: 11/29/2022]
Abstract
How are water's material properties encoded within the structure of the water molecule? This is pertinent to understanding Earth's living systems, its materials, its geochemistry and geophysics, and a broad spectrum of its industrial chemistry. Water has distinctive liquid and solid properties: It is highly cohesive. It has volumetric anomalies-water's solid (ice) floats on its liquid; pressure can melt the solid rather than freezing the liquid; heating can shrink the liquid. It has more solid phases than other materials. Its supercooled liquid has divergent thermodynamic response functions. Its glassy state is neither fragile nor strong. Its component ions-hydroxide and protons-diffuse much faster than other ions. Aqueous solvation of ions or oils entails large entropies and heat capacities. We review how these properties are encoded within water's molecular structure and energies, as understood from theories, simulations, and experiments. Like simpler liquids, water molecules are nearly spherical and interact with each other through van der Waals forces. Unlike simpler liquids, water's orientation-dependent hydrogen bonding leads to open tetrahedral cage-like structuring that contributes to its remarkable volumetric and thermal properties.
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Affiliation(s)
- Emiliano Brini
- Laufer
Center for Physical and Quantitative Biology, Department of Physics and Astronomy, and Department of
Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | - Christopher J. Fennell
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Marivi Fernandez-Serra
- Laufer
Center for Physical and Quantitative Biology, Department of Physics and Astronomy, and Department of
Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | - Barbara Hribar-Lee
- Faculty
of Chemistry and Chemical Technology, University
of Ljubljana, Večna
pot 113, SI-1000 Ljubljana, Slovenia
| | - Miha Lukšič
- Faculty
of Chemistry and Chemical Technology, University
of Ljubljana, Večna
pot 113, SI-1000 Ljubljana, Slovenia
| | - Ken A. Dill
- Laufer
Center for Physical and Quantitative Biology, Department of Physics and Astronomy, and Department of
Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
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